In the beginner's mind there are many possibilities.
In the expert's mind there are few.
If you are completely new to meditation, you may want to try meditating first while at home, not on your bicycle. The following instructions are by Rabbi Ted Falcon, and used with permission.
(Read these instructions until you are comfortable with them, and then try them out.)
Find a place when you will not be disturbed for at least ten minutes, and make yourself comfortable. Settle into your chair, or sit on the floor with your back straight. You will wish to be at ease, but remain on this side of sleep.
Gently let your eyes close, and take some time to become aware of how your body feels. Do a gentle but thorough internal scan from your feet all the way up your legs, then from your hands all the way up your arms. Then begin at the base of your spine and scan all the way up to your neck. Discover the sensations in different areas of your body as carefully as you can. And then focus on your neck, your jaw, the back of your head, then your face. Finally, appreciate how your forehead feels, and then your scalp.
You might find it helpful to repeat this body scan. The goal is simply to become more gently aware, without trying to change anything.
Then become aware of your thoughts. Become aware of the "conversations" you are holding with yourself. Again, the goal is simple awareness. There is no need to change or judge anything.
Finally, become aware of your breathing. Stay with your breathing as long as you are able. When you find your thoughts straying, or when you find bodily sensations intruding, be aware of them, and then return your focus to the breath.
When you are ready to conclude your moments of meditation, take a few deeper breaths, and again become aware of how your body feels. Slowly let your eyes open, stretch, and give yourself a few moments before you rise.
This process of creating a meditative space can be used by itself, or as an introduction to any other meditative process. It is helpful to have as a basic frame such as this which can also serve to help you relax at moments of stress.